The invention is based on a method as generally defined hereinafter and relates further to internal combustion engines, injection pumps and apparatus for performing the method according to the invention.
Single-cylinder plug-in fuel injection pumps, called plug-in pumps, are advantageously used whenever the expenditure for a series or distributor injection pump is excessive in the case of engines with a low cylinder output (approximately 2 to 30 KW per cylinder), and whenever the injection pumps are to be mounted as close as possible to the injection nozzle of the associated engine as a result of the use of short pressure lines and the improved injection conditions thereby attainable. Plug-in pumps do not have their own drive mechanism; instead, they are driven by a camshaft which is part of the engine. The regulation of the injection quantity is effected by way of a governor rod which is part of the engine, this rod being located, like the supply quantity adjusting member of the plug-in pump, below the associated fastening flange inside the pump fitting of the engine. Pumps of this type are known, such as those of the Robert Bosch GmbH, Stuttgart, Federal Republic of Germany, and designated PF 1Q . . . and PFR 1K . . . (for instance, see the pamphlet entitled "Injection Equipment for Diesel Engines with Injection Pump Type PF", VDT-UBP 001/6B by Robert Bosch GmbH, Stuttgart); each of these pumps, before being mounted on a particular engine, is adjusted at a test bench, using a test pedestal adapted to a set-point supply quantity which is identical for all pumps of the same series, then inserted in the associated pump fitting of the engine with the aid of an adjusting apparatus and secured there. Since in the known pumps the adjusting apparatus provided with a fixation pin fixes solely the mounted position at the pump fitting, the engine must be precisely adjusted on the test bench once again in terms of the supply quantities of the individual plug-in pumps, which is very expensive. Adjustable coupling parts of the governor rod belonging to the engine have to be coupled to the supply quantity adjusting member of the plug-in pumps and adjusted. If one of the plug-in pumps is replaced, this test procedure must be performed once again.
The above disadvantage also applies to plug-in pumps of the type shown in U.S. Pat. No. 2,975,776, because the adjusting apparatus used there, comprising a positional fixation pin for the securing flange and a pin for the positionally correct mounting of the pinion through a gap in gear teeth in the governor rod belonging to the engine, merely prevents incorrect mounting; a precise setting of supply quantity which will be retained even if the pump is replaced is neither intended nor possible in this apparatus. In order to be able to replace individual pumps or pumping elements in the case of damage without performing a new basic setting for all the injection pumps, a method and an associated injection pump for the method have each been proposed by Austrian Pat. No. 269 560 and German Pat. No. 1 050 604. In these patents, pumping elements embodied in the manner of plug-in pumps which have been adjusted on a test pedestal in terms of their supply quantity are combined in a common pump housing and are driven by a governor rod located in the pump housing. With these types of apparatus, although the individual pumping elements can be replaced, the governor rod which is the same for all the pumping elements must still have adjustable mating elements for the coupling elements of the supply quantity adjustment members; the associating adjusting devices are very expensive and laborious, and the overall apparatus is poorly adapted to being mounted on an engine.
The object of the invention is to simplify the method for mounting the plug-in pumps as well as the associated pumps and the internal combustion engine in such a way that not only the method but also the plug-in pumps and the governor elements on the internal combustion engine are all made less expensive.